(1. Department of Geotechnical Engineering，Tongji University，Shanghai 200092，China；2. Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education，Tongji University，Shanghai 200092，China；3. College of Engineering，Tibet University，Lhasa，Tibet 850012，China；4. China Fortune Land Development Co.，Ltd.，Jiaozuo，Henan 454950，China)
Abstract：Rock-like specimens with different angles of pre-existing cracks，made by embedded thin sheet method，were using to study the fracturing behaviors and mechanical properties of hydro-mechanical coupled cracks. In this study，1，3 and 5 MPa water pressure were applied inside the pre-existing crack respectively and led to the specimen failure with external compression loading under 6 MPa confining pressure. By analyzing the mechanical properties and failure patterns，the test showed that the failure mode changes from ductile failure to brittle failure with the increase of water pressure. The triaxial strength，post-peak residual strength and elastic modulus all decrease when water pressure increases，and decreases firstly and then increases when pre-existing crack?s angle increases. The fracture angles of intact specimens increases with water pressure increases and the failure pattern transforms from shear failure to splitting failure. When the angle of the pre-existing crack is small，the failure mode of cracked specimen affected by water pressure，and X-shaped crack morphology was observed under high water pressure. When the angle of the pre-existing crack between 60°and 90°，the fracture surface presents a single inclined plane，and the angle of the fracture surface is basically identical with the pre-existing crack.
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2019, Vol. 38 
